Diffusion transfer color process and element utilizing a processing composition comprising a coalescing latex dispersion

ABSTRACT

THE PRESENT INVENTION RELATES TO A COMPOSITE PHOTOGRAPHIC DIFFUSION TRNASFER PROCESS COLOR FILM UNIT WHICH INCLUDES RUPTURABLE CONTAINER MEANS RETAINING PROCESSING COMPOSITION CONTAINING AN INSOLUBLE POLYMERIC DISPERSION ADAPTED UPON LOSS OF PROCESSING COMPOSITION SOLVENT TO COALESCE AT AMBIENT TEMPERATURES FOR DISTRIBUTION BETWEEN PHOTOSENSITIVE AND IMAGE RECEPTIVE ELEMENTS OF THE UNIT.

Aug. 3, 1971 T. w. MILLIGAN DIFFUSION TRANSFER COLOR PROCESS AND ELEMENTUTILIZING A PROCESSING COMPOSITION COMPRISING A COALESGING LATEXDISPERSION 4 Sheets-Sheet 1 Filed Oct. 20, 1969 FIG. I

INVENTOR. TE RRY W. Ml LLIGAN g- 3, 1971 T. w. MILLIGAN 3,5

DIP FUSION TRANSFER COLOR PROCESS AND ELEMENT UTILIZING A PROCESSINGCOMPOSITION COMPRISING A COALESCING LATEX DISPERSION 4 Sheets-sheet 2Filed OCT. 20, 1969 a m N 0 I MN NN A QM TERRY w. MILLIGAN /ww n and Mcowl AT TORNEYS 3, 1971 'r. w. MILLIGAN 3,597,197

DIFFUSION TRANSFER COLOR PROCESS AND ELEMENT UTILIZING A PROCESSINGCOMPOSITION COMPRISING A COALESCING LATEX DISPERSION 4 Sheets-Sheet 5Filed Oct. 20, 1969 INVENTQR. TERRY w. MILLIGAN BY @how n, WW2,

wrul W006 7% 7nd ATTORNEYS Aug. 3, 1971 T. w. MILLIGAN 3,597,197

DIFFUSION TRANSFER COLOR PROCESS AND ELEMENT UTILIZING A PROCESSINGCOMPOSITION COMPRISING A COALESCING LATEX DISPERSION 4 Sheets-Sheet 4Filed Oct. 20, 1969 INVENTOK TERRY W. MILLIGAM Wm 00 gm W W M p UnitedStates Patent O US. Cl. 963 44 Claims ABSTRACT OF THE DISCLOSURE Thepresent invention relates to a composite photographic diffusion transferprocess color film unit which includes rupturable container meansretaining processing composition containing an insoluble polymericdispersion adapted upon loss of processing composition solvent tocoalesce at ambient temperatures for distribution between photosensitiveand image receptive elements of the unit.

The present invention relates to photography and, more particularly, tophotographic products particularly adapted for employment inphotographic diffusion transfer color processes.

The primary objects of the present invention are to provide photographicproducts particularly adapted for employment in diffusion transfer colorprocesses; to provide photographic products which comprise aphotosensitive composite structure which contains a plurality ofessential layers including a first dimensionally stable, liquidimpermeable layer, a photosensitive silver halide emulsion layer havinga dye image-forming material associated therewith which is soluble anddiffusible at a first processing composition solvent concentration, apolymeric layer dyeable by the dye image-forming material, and a seconddimensionally stable, liquid impermeable layer, transparent to incidentradiation, in combination with a rupturable container retaining aprocessing composition containing dispersed therein a processingcomposition insoluble particulate polymeric dispersion adapted upon lossof processing composition solvent to coalesce at ambient temperaturesfixedly positioned and extending transverse a leading edge of thecomposite photosensitive structure whereby to effect, upon applicationof compressive pressure, discharge of the processing compositionintermediate the dyeable polymeric layer and photosensitive silverhalide emulsion next adjacent thereto containing a quantity of thepolymeric dispersion sufficient upon coalescence to provide asubstantially continuous, diffusible dye image-forming materialimpermeable polymeric layer disposed intermediate the dyeable polymericlayer and the photosensitive silver halide emulsion layer next adjacent;to provide a diffusion transfer color film unit of the last-identifiedtype including an opacifying agent disposed intermediate the dyeablepolymeric layer and the photosensitive emulsion next adjacent thereto ina quantity sufficient to mask the dye image-forming material; to providea diffusion transfer color film unit of the last-identified typeprocessing the opacifying agent initially present in the processingcomposition for discharge intermediate the dyeable polymeric layer andthe photosensitive silver halide emulsion next adjacent thereto uponapplication of compressive pressure to the container and distribution ofits contents intermediate the layers; and to provide photographicdiffusion transfer color processes employing such products.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

3,597,197 Patented Aug. 3, 1971 The invention accordingly comprises theproduct possessing the features, properties and the relation ofcomponents and the process involving the several steps and the relationand order of one or more of such steps with respect to each of theothers which are exemplified in the following detailed disclosure, andthe scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a photographic film unit embodying theinvention;

FIGS. 2, 4 and 6 are diagrammatic enlarged crosssectional views of thefilm unit of FIG. 1, along section line 2-2, illustrating theassociation of elements during the three illustrated stages of theperformance of a diffusion transfer process, for the production of amulticolor transfer image according to the invention, the thickness ofthe various materials being exaggerated, and wherein FIG. 2 representsan exposure stage, FIG. 4 represents a processing stage and FIG. 6represents a product of the process; and

FIGS. 3, 5 and 7 are diagrammatic, further enlarged cross-sectionalviews of the film unit of FIGS. 2, 4 and 6, along section lines 33, 55and 77, respectively, further illustrating, in detail, the arrangementof layers comprising the photosensitive laminate during the threeillustrated stages of the transfer process.

As disclosed in US. Pat. No. 2,983,606, issued May 9, 1961, aphotosensitive element containing a dye developer, that is, a dye whichis a silver halide developing agent, and a silver halide emulsion may beexposed and wetted by a liquid processing composition, for example, byimmersion, coating, spraying, flowing, etc., in the dark, and theexposed photosensitive element superposed prior to, during or afterwetting, on a sheetlike support element which may be utilized as animage-receiving element. In a preferred embodiment, the liquidprocessing composition is applied to the photosensitive element in asubstantially uniform layer as the photosensitive element is broughtinto superposed relationship with the image-receiving layer. The liquidprocessing composition, positioned intermediate the photosensitiveelement and the image-receiving layer, permeates the emulsion toinitiate development of the latent image contained therein. The dyedeveloper is immobilized or precipitated in exposed areas as aconsequence of the development of the latent image. This immobilizationis apparently, at least in part, due to a change in the solubilitycharacteristics of the dye developer upon oxidation and especially asregards its solubility in alkaline solutions. It may also be due in partto a tanning effect on the emulsion by oxidized developing agent, and inpart to a localized exhaustion of alkali as a result of development. Inunexposed and partially exposed areas of the emulsion, the dye developeris unreacted and diffusible and thus provides an imagewise distributionof unoxidized dye developer dissolved in the liquid processingcomposition, as a function of the point-to-point degree of exposure ofthe silver halide emulsion. At least part of this imagewise distributionof unoxidized dye developer is transferred, by imbibition, to asuperposed image-receiving layer or element, said transfer substantiallyexeluding oxidized dye developer. The image-receiving element receives adepth-Wise diffusion, from the developed emulsion, of unoxidized dyedeveloper without appreciably disturbing the imagewise distributionthereof to provide the reversed or positive color image of the developedimage. The image-receiving element may contain agents adapted to mordantor otherwise fix the diffused, unoxidized dye developer. If the color ofthe transferred dye developer is affected by changes in the pH of theimage-receiwing element, this pH may be adjusted in accordance withwell-known techniques to provide a pH affording the desired color. Thedesired positive image is revealed by stripping the image-receivinglayer from the photosensitive element at the end of a suitableimbibition period.

The dye developers, as noted above, are compounds which contain, in thesame molecule, both the chromophoric system of a dye and also a silverhalide developing function. By a silver halide developing function ismeant a grouping adapted to develop exposed silver halide. A preferredsilver halide development function is a hydroquinonyl group. Othersuitable developing functions include ortho-dihydroxyp-henyl andorthoand para-amino substituted hydroxyphenyl groups. In general, thedevelopment function includes a benzenoid developing function, that is,an aromatic developing group which forms quinonoid or quinone substanceswhen oxidized.

Multicolor images may be obtained using color imageforming componentssuch as, for example, the previously mentioned dye developers, indiffusion transfer processes by several techniques. One such techniquecontemplates obtaining multicolor transfer images utilizing dyedevelopers by employment of an integral multilayer photosensitiveelement, such as is disclosed in the aforementioned U.S. Pat. No.2,983,606, and particularly with reference to FIG. 9 of the patentsdrawing, wherein at least two selectively sensitized photosensitivestrata, superposed on a single support, are processed, simultaneouslyand without separation, with a single, common image-receiving layer. Asuitable arrangement of this type comprises a support carrying ared-sensitive silver halide emulsion stratum, a green-sensitive silverhalide emulsion stratum and a blue-sensitive silver halide emulsionstratum, said emulsions having associated therewith, respectively, forexample, a cyan dye developer, a magenta dye developer and a yellow dyedeveloper. The dye developer may be utilized in the silver halideemulsion layer, for example, in the form of particles, or it may beemployed as a layer behind the appropriate silver halide emulsionstrata. Each set of silver halide emulsion and associated dye developerstrata are disclosed to be optionally separated from other sets bysuitable interlayers, for example, by a layer of gelatin or polyvinylalcohol. In certain instances, it may be desirable to incorporate ayellow filter in front of the green-sensitive emulsion and such yellowfilter may be incorporated in an interlayer. However, where desirable, ayellow dye developer of the appropriate spectral characteristics andpresent in a state capable of functioning as a yellow filter may beemployed. In such instances, a separate yellow filter may be omitted.

The dye developers are preferably selected for their ability to providecolors that are useful in carrying out subtractive color photography,that is, the previously mentioned cyan, magenta and yellow. The dyedevelopers employed may be incorporated in the respective silver halideemulsion or, in the preferred embodiment, in a separate layer behind therespective silver halide emulsion. Specifically, the dye developer may,for example, be in a coating or layer behind the respective silverhalide emulsion and such a layer of dye developer may be applied by useof a coating solution containing about 0.5 to 8%, by weight, of therespective dye developer distributed in a film-forming natural, orsynthetic, polymer, for example, gelatin, polyvinyl alcohol, and thelike, adapted to be permeated by the chosen diffusion transfer fluidprocessing composition.

As examples of materials, for use as the image-receiving layer, mentionmay be made of solution dyeable polymers such as nylon as, for example,N-methoxymethyl polyhexamethylene adiparnide; partially hydrolyzedpoly-vinyl acetate; polyvinyl alcohol with or without plasticizers;cellulose acetate with filler as, for example, one-half celluloseacetate and one-half oleic acid; gelatin; and other materials of asimilar nature. Preferred materials comprise polyvinyl alcohol orgelatin containing a dye mordant such as poly-4-vinylpyridine, asdisclosed in U.S. Pat. No. 3,148,061, issued Sept. 8, 1964.

As disclosed in the previously cited patents, the liquid processingcomposition referred to for effecting multicolor diffusion transferprocesses comprises an aqueous solution of an alkaline material, forexample, diethylamine, sodium hydroxide or sodium carbonate and thelike, and preferably possessing a pH in excess of 12, and mostpreferably includes a viscosityincreasing compound constituting afilm-forming material of the type which, when the composition is spreadand dried, forms a relatively firm and relatively stable film. Thefilm-forming materials disclosed comprise high molecular weight polymerssuch as polymeric, water-soluble ethers which are inert to an alkalinesolution such as, for example, a hydroxyethyl cellulose or sodiumcarboxymethyl cellulose. Additionally, film-forming materials orthickening agents whose ability to increase viscosity is substantiallyunaffected if left in solution for a long period of time are alsodisclosed to be capable of utilization. As stated, the film-formingmaterial is preferably contained in the processing composition in suchsuitable quantities as to impart to the composition a viscosity inexcess of cps. at a temperature of approximately 24 C. and preferably inthe order of 100,000 cps. to 200,000 cps. at that temperature.

In accordance with aforementioned US. Pat. No. 2,- 983,606, animage-receiving layer of the type disclosed in that patent need not beseparated from its superposed contact with the photosensitive element,subsequent to transfer image formation, if the image-receiving elementis transparent and a processing composition containing a substancerendering the processing composition layer opaque is spread between theimage-receiving layer and the silver halide emulsion or emulsions.

However, it has been found, if the image-receiving element is maintainedin contact with the photosensitive element, subsequent to dye developertransfer image formation, and includes the presence of an alkalineprocessing composition, necessarily having a pH at which dye developer,for example, in reduced form, diffuses to form the dye transfer image,intermediate the elements, the transfer image thus formed is unstableover an extended period of time. The dye image instability is due, atleast in part to the presence of what is, in general, a relatively highpH alkaline composition in intimate contact with the dye or dyes formingthe image. This contact itself provides instability to the molecularstructure of dye by, for example catalyzing degradation and undesirablestructural shifts effecting the spectral absorption characteristics ofthe image dye. In addition, the presence of an alkaline composition,possessing a pH at which the dye, for example, in reduced form,diffuses, also provides an integral dynamic system wherein oxidized dye,immobilized in areas of the photosensitive element, as a function of itsdevelopment, with the passage of time attempts to generate, in suchareas, an equilibrium between oxidized and reduced dye. In that the pHof the dynamic system is such that diffusion of the reduced form of thedye will occur, such reduced dye will, at least in part, transfer to theimage-receiving layer and the resultant diffusion will imbalance theequilibrium, in such areas of the photosensitive element, in favor ofadditional formation of reduced dye. As a function of the efiiciency ofthe image-receiving layer, as a dye sink, such nonimagewise dyeing ofthe image-carrying layer still further imbalances the equilibrium infavor of the additional formation of dye in reduced, diffusible form.Under such circumstances, the transfer image definition, originallycarried by the image-receiving layer, will suffer a continuous decreasein the delta between the images maximum and minimum densities and may,ultimately, result in the image-receiving elements,

loss of all semblance of image definition; merely becoming a polymericstratum carrying a relatively uniform overall dyeing.

Any attempt to decrease the dye sink capacity of the image-carryinglayer, for example, by reduction of its mordant capacity, in order toalleviate, at least to an eX- tent, the action of the image-receivinglayer as a dye sink, however, will enhance diifusion of the dye,comprising the transfer image, from the image-carrying layer, to theremainder of the element due, at least in part, to the continuedpresence of the alkaline composition having a pH at which the reducedform of the dye, forming the transfer image, is diifusible. The ultimateresult is substantially the same overall image distortion as occurs whenthe image-receiving layer acts as a dye sink, with the exception thatthe dye is more extensively distributed throughout the film unit and theultimate overall dyeing of the image-receiving layer itself is of lowersaturation.

The problems inherent in fabricating a film unit of the type wherein theimage-receiving element, the alkaline processing composition and thephotosensitive element are maintained in contiguous contact subsequentto dye transfer image formation, for example, a film unit of the typedescribed hereinbefore with reference to aforementioned U.S. Pat. No.2,983,606, may be effectively obviated by fabrication of a film unit inaccordance with the physical parameters specifically set forth incopending US. Pats. Nos. 3,415,644; 3,415,645; and 3,415,646, issuedDec. 10, 1969, respectively, in the name of Edwin H. Land.

Specifically an integral photographic film unit particularly adapted forthe production of a dye transfer image of unexpectedly improvedstability and other properties, by a color diffusion transfer processwill be constructed, for example, in accordance with aforementioned US.Pat. No. 3,415,644, to include a photosensitive element comprising alaminate having, in sequence, as essential layers, a dimensionallystable opaque layer; a photosensitive silver halide emulsion layerhaving associated therewith dye image-providing material which issoluble and diffusible, in alkali, at a first pH; an alkaline solutionpermeable polymeric layer dyeable by the dye image-providing material; apolymeric acid layer containing sufficient acidifying groups to effectreduction, subsequent to substantial transfer dye image formation, of aselected processing solution having the first pH to a second pH at whichsaid dye image-providing material is insoluble and nondiffusible; and adimensionally stable transparent layer. In combination with thelaminate, a rupturable containing retaining an aqueous alkalineprocessing composition having the first pH and containing an opacifyingagent, in a quantity sufficient to mask the dye image-providingmaterial, is fixedly positioned and extends transverse a leading edge ofthe laminate whereby to effect unidirectional dischargre of thecontainers contents between the alkaline solution permeable and dyeablepolymeric layer and the photosensitive silver halide emulsion layer nextadjacent thereto, upon application of compressive force to thecontainer.

It will also be recognized that the dimensionally stable polymericsupport layer next adjacent the photosensitive silver halide emulsionlayer or layers may be transparent, as disclosed in aforementioned U.S.Pat. No. 3,415,646, and that in such instance the opacifying agent maybe initially dispersed in the composite film unit intermediate thedyeable polymeric layer and the silver halide emulsion layer nextadjacent, as disclosed in aforementioned US. Pat. No. 3,415,645.

Employment of the last-mentioned film units, according to the describedcolor diffusion transfer photographic process, specifically provides forthe production of a highly stable color transfer image accomplished, atleast in part, by effectively obviating the previously discusseddisadvantages of the prior art products and processes, by in processadjustment of the environmental pH of the film unit from a pH at whichtransfer processing is Operative to a pH at which dye transfer isinoperative subsequent to substantial transfer image formation. Thestable color transfer image is obtained irrespective of the fact thatthe film unit is maintained as an integral laminate unit duringexposure, processing, viewing, and storage of the unit, which transferimage exhibits the required maximum and minimum dye transfer imagedensities, dye saturation, hues and definition.

However, film units fabricated in accordance with the parameters setforth above specifically require the presence of the stated polymericacid component to effect in situ process adjustment of the film unitsoperational pH range.

Specifically, the film units require the presence of a polymeric acidlayer such as, for example, of the type set forth in US. Pat. No.3,362,819 which, most preferably, includes the presence of an inerttiming or spacer layer intermediate the polymeric acid layer carried ona support and the image-receiving layer.

As set forth in the last-mentioned patent, the polymeric acid layercomprises polymers which contain acid groups, such as carboxylic acidand sulfonic acid groups, which are capable of forming salts with alkalimetals, such as sodium, potassium etc., or with organic bases,particularly quaternary ammonium bases, such as tetramethyl ammoniumhydroxide, or potentially acid-yielding groups, such as anhydrides orlactones, or other groups which are capable of reacting with bases tocapture and retain them. The acid-reacting group is, of course,nondiifusible from the acid polymer layer. In the preferred embodimentsdisclosed, the acid polymer contains free carboxyl groups and thetransfer processing composition employed contains a large concentrationof sodium and/ or potassium ions. The acid polymers stated to be mostuseful are characterized by containing free carboxyl groups, beinginsoluble in water in the free acid form, and by forming water-solublesodium and/or potassium salts. One may also employ polymers containingcarboxylic acid anhydride groups, at least some of which preferably havebeen converted to free carboxyl groups prior to imbibition. While themost readily available polymeric acids are derivatives of cellulose orof vinyl polymers, polymeric acids from other classes of polymers may beused. As examples of specific polymeric acids set forth in theapplication, mention may be made of dibasic acid half-ester derivativesof cellulose which derivatives contain free carboxyl groups, e.g.,cellulose acetate hydrogen phthalate, cellulose acetate hydrogenglutarate, cellulose acetate hydrogen succinate, ethyl cellulosehydrogen succinate, ethyl cellulose acetate hydrogen succinate,cellulose acetate hydrogen succinate hydrogen phthalate; ether and esterderivatives or cellulose modified with sulfoanhydrides, e.g., withortho-sulfobenzoic anhydride; polystyrene sulfonic acid; carboxymethylcellulose; polyvinyl hydrogen phthalate; polyvinyl acetate hydrogenphthalate; polyacrylic acid; acetals of polyvinyl alcohol with carboxyor sulfo substituted aldehydes, e.g., 0-, m-, or p-benzaldehyde sulfonicacid or carboxylic acid; partial esters of ethylene/ maleic anhydridecopolymers; partial esters of methylvinyl ether/maleic anhydridecopolymers; etc.

As previously noted, the pH of the processing composition preferably isof the order of at least 12 to 14. The acid polymer layer is disclosedto contain at least sufficient acid groups to effect a reduction in thepH of the image layer from a pH of about 12 to 14 to a pH of at least 11or lower at the end of the imbibition period, and preferably to a pH ofabout 5 to 8 within a short time after imbibition, thus requiring, ofcourse, that the action of the polymeric acid be accurately socontrolled as not to interfere with either development of the negativeor image transfer of unoxidized dye developers. For this reason, the pHof the image layer must be kept at a functional transfer level, forexample, 12 to 14 until the dye image has been formed after which the pHis reduced very rapidly to a pH below that at which dye transfer may beaccomplished, for example, at least about 11 and preferably about pH 9to 10. Unoxidized dye developers containing hydroquinonyl developingradicals diffuse from the negative to the positive as the sodium orother alkali salt. The diffusion rate of such dye image-formingcomponents thus is at least partly a function of the alkaliconcentration, and it is necessary that the pH of the image layer remainon the order of, for example, 12 to 14 until transfer of the necessaryquantity of dye has been accomplished. The subsequent pH reduction, inaddition to its desirable effect upon image light stability, serves ahighly valuable photographic function by substantially terminatingfurther dye transfer.

In order to prevent premature pH reduction during transfer processing,as evidenced, for example, by an undesired reduction in positive imagedensity, the acid groups are disclosed to be so distributed in the acidpolymer layer that the rate of their availability to the alkali iscontrollable, e.g., as a function of the rate of swelling of the polymerlayer which rate in turn has a direct relationship to the diffusion rateof the alkali ions. The desired distribution of the acid groups in theacid polymer layer may be effected by mixing the acid polymer with apolymer free of acid groups, or lower in concentration of acid groups,and compatible therewith, or by using only the acid polymer butselecting one having a relatively lower proportion of acid groups. Theseembodiments are illustrated, respectively, in the cited copendingapplication, by (a) a mixture of cellulose acetate and cellulose acetatehydrogen phthalate and (b) a cellulose acetate hydrogen phthalatepolymer having a much lower percentage of phthalyl groups than thefirst-mentioned cellulose acetate hydrogen phthalate.

It is also there disclosed that the layer containing the polymeric acidmay contain a water-insoluble polymer, preferably a cellulose ester,which acts to control or modulate the rate at which the alkali salt ofthe polymer acid is formed. As examples of cellulose esters contemplatedfor use, mention is made of cellulose acetate, cellulose acetatebutyrate, etc. The particular polymers and combinations of polymersemployed in any given embodiment are, of course, selected so as to haveadequate wet and dry strength and when necessary or desirable, suitablesubcoats are employed to help the various polymeric layers adhere toeach other during storage and use.

The inert spacer layer of the last-mentioned patent, for example, aninert spacer layer comprising polyvinyl alcohol or gelatin, acts to timecontrol the pH reduction by the polymeric acid layer. This timing isdisclosed to be a function of the rate at which the alkali diffusesthrough the inert spacer layer. It is there stated to have been foundthat the pH does not drop until the alkali has passed through the spacerlayer, i.e., the pH is not reduced to any significant extent by the meredifiusion into the interlayer, but the pH drops quite rapidly once thealkali diffuses through the spacer layer.

It has now been quite unexpectedly discovered that the problems inherentin fabricating a film unit of the type where the image-receivingelement, the alkali processing composition and the photosensitiveelement are maintained in contiguous contact during processing andsubsequent to dye transfer image formation, for example, a film unit ofthe type described, with reference to aforementioned US. Pat. No.2,983,606, may be effectively obviated in a considerably simplifiedmanner by fabrication of a film unit in accordance with the physicalparameters detailed below.

Specifically, it has been quite unexpectedly discovered that an integralphotographic film unit of simplified construction and particularlyadapted for the production of dye transfer images of unexpectedlyimproved stability and other desirable properties by a color diffusiontransfer process will be constructed to include a photosensitive elementcomprising a composite structure possessing, in sequence, as essentiallayers, a first dimensionally stable layer, a photosensitive silverhalide emulsion layer having associated therewith a dye image-formingmaterial which is soluble and diffusible as a function of the pointto-point degree of emulsion photoexposure, a polymeric layer dyeable bythe dye image-forming material, and a second dimensionally stable layertransparent to incident actinic radiation. In combination with thecomposite structure, a rupturable container retaining a processingcomposition containing a particulate dispersion of processingcomposition insoluble polymer, as a discontinuous phase, which isadapted in the absence of processing composition solvent, the continuousphase, to coalesce at ambient temperature, is fixedly positioned andextends transverse a leading edge of the composite structure whereby toeffect, upon application of compressive pressure, discharge of theprocessing composition intermediate the dyeable polymeric layer and thephotosensitive silver halide emulsion and associated dye image-formingmaterial next adjacent, in a quantity sufficient upon loss of processingcomposition solvent to provide a substantially continuous, dyeimage-forming material impermeable polymeric layer, upon coalescence ofprocessing composition retained polymeric dispersion, intermediate thedyeable polymeric layer and next adjacent photosensitive silver halideemulsion. Although both dimensionally stable layers may be transparentand in such instance, an opacifying agent may be initially dispersedintermediate the dyeable polymeric layer and the next adjacent silverhalide emulsion layer, in a quantity sufiicient to mask the dyeimage-forming material, such opacifying agent will preferably bedisposed within the processing composition, in a quantity sufiicient tomask the dye image-forming material upon distribution of the processingcomposition intermediate the last-stated layers, and, most preferably,the dimensionally stable layer next adjacent the photosensitive silverhalide emulsion layer will be opaque with respect to externally derivedincident actinic radiation.

In view of the fact that the preferred dye image-providing materialscomprise dyes which are silver halide developing agents, as statedabove, for purposes of simplicity and clarity, the present inventionwill be further described hereinafter in terms of such dyes, withoutlimitation of the invention to the illustrative dyes denoted, and, inaddition, the photographic film unit structure will be detailedhereinafter employing the last-mentioned preferred structuralembodiment, without limitation of the invention to the preferredstructure denoted.

In a preferred embodiment of the present invention, the film unit isspecifically adapted to provide for the production of a multicolor dyetransfer image and the photosensitive laminate comprises, in order ofessential layers, the dimensionally stable opaque layer; at least twoselectively sensitized silver halide emulsion strata each having dyeimage-providing materials of predetermined color associated therewithwhich are soluble and diffusible in alkaline processing composition as afunction of the point-to-point degree of exposure of the respectiveassociated silver halide emulsion strata; an alkaline solution permeablepolymeric layer dyeable by the dye imageproviding materials; and thedimensionally stable transparent layer.

The silver halide emulsions comprising the multicolor photosensitivelaminate preferably possess predominant spectral sensitivity to separateregions of the spectrum and each has associated therewith a dye, whichis a silver halide developing agent and is, most preferably,substantially soluble in the reduced form only at a selected pHpossessing subsequent to processing a spectral absorption rangesubstantially complementary to the predominant sensitivity range of itsassociated emulsion.

In the preferred embodiment, each of the emulsion strata, and itsassociated dye, is separated from the remaining emulsion strata, andtheir associated dye, by separate alkaline solution permeable polymericinterlayers.

In such preferred embodiment of the invention, the silver halideemulsion comprises photosensitive silver halide dispersed in gelatin andis about 0.6 to 6 microns in thickmess; the dye itself is dispersed inan aqueous alkaline solution polymeric binder, preferably gelatin, as aseparate layer about 1 to 7 microns in thickness; the alkaline solutionpermeable polymeric interlayers, preferably gelatin, are about 1 tomicrons in thickness; the alkaline solution dveable polymeric layer istransparent and about 0.25 to 0.4 mil in thickness; and each of thedimensionally stable opaque and transparent layers are alkaline solutionimpermeable, most preferably processing composition vapor permeable andabout 2 to 6 mils in thickness. It will be specifically recognized thatthe relative dimensions recited above may be appropriately modified, inaccordance with the desires of the operator, with respect to thespecific product to be ultimately prepared.

In the preferred embodiment of the present inventions film unit for theproduction of a multicolor transfer image, the respective silver halide/dye developer units of the photosensitive element will be in the form ofa tripack configuration which will ordinarily comprise a cyan dyedeveloper/red-sensitive emulsion unit contiguous the dimensionallystable opaque layer, the yellow dye developer/ blue-sensitive emulsionunit most distant from the opaque layer and the magenta dyedeveloper/green-sensitive emulsion unit intermediate those units,recognizing that that the relative order of such units may be varied inaccordance with the desires of the operator.

Reference is now made to FIGS. 1 through 7 of the drawings wherein thereis illustrated a preferred film unit of the present invention andwherein like members, appearing in the various figures, refer to likecomponents.

As illustrated in the drawings, FIG. 1 sets forth a perspective view ofthe film unit, designated 10, and each of FIGS. 2 through 7 illustratediagrammatic cross-sectional views of film unit 10, along the statedsection lines 22, 33, 55, and 77, during the various depicted stages inthe performance of a photographic diffusion transfer process as detailedhereinafter.

Film unit 10 comprises rupturable container 11, retaining, prior toprocessing, aqueous alkaline solution 12, and photosensitive laminate 13including, in order, dimensionally stable opaque layer 14, preferably anactinic radiation-opaque flexible sheet material; cyan dye developerlayer 15; red-sensitive silver halide emulsion layer 16; interlayer 17;magenta dye developer layer 18; green-sensitive silver halide emulsionlayer 19; interlayer 20; yellow dye developer layer 21; blue-sensitivesilver halide emulsion layer 22; auxiliary layer 23, which may containan auxiliary sliver halide developing agent; image-receiving layer 24;and dimensionally stable transparent layer 27,

preferably an actinic radiation transmissive flexible sheet material.

The structural integrity of laminate 13 may be maintained, at least inpart, by the adhesive capacity exhibited between the various layerscomprising the laminate at their opposed surfaces. However, the adhesivecapacity exhibited at an interface intermediate image-receiving layer 24and the silver halide emulsion layer next adjacent thereto, for example,intermediate image-receiving layer 24 and auxiliary layer 23 asillustrated in FIGS. 2 through 7, should be less than that exhibited atthe interface between the opposed surfaces of the remainder of thelayers forming the laminate, in order to facilitate distribution ofprocessing solution 12 intermediate the stated image-receiving layer 24and the silver halide emulsion layer next adjacent thereto. Thelaminates structural integrity may also be enhanced or provided, inwhole or in part, by providing a binding member extending around, forexample, the edges of laminate 13, and maintaining the layers comprisingthe laminate intact, except at the interface between layers 23 and 24during distribution of alkaline solution 12 intermediate those layers.As illustrated in the figures, the binding member may comprise apressure-sensitive tape 28 securing and or maintaining the layers oflaminate 13 together at its respective edges.

Tape 28 will also act to maintain processing solution 12 intermediateimage-receiving layer 24 and the silver emulsion layer next adjacentthereto, upon application of compressive pressure to pod 11 anddistribution of its contents intermediate the stated layers. Under suchcircumstances, binder tape 28 wil act to prevent leakage of fluidprocessing composition from the film units laminate during andsubsequent to photographic processing.

Rupturable container 11 may be of the type shown and described in any ofU.S. Pats. Nos. 2,543,181; 2,634,- 886; 2,653,732; 2,723,051; 3,056,492;3,056,491; 3,152,- 515; and the like. In general, such containers willcomprise a rectangular blank of fluidand air-impervious sheet materialfolded longitudinally upon itself to form two walls 29 which are sealedto one another along their longitudinal and end margins to form a cavityin which processing solution 12 is retained. The longitudinal marginalseal 30 is made weaker than the end seals 31 so as to become unsealed inresponse to the hydraulic pressure generated within the fluid contents12 of the container by the application of compressive pressure to walls29 0f the container.

As illustrated in FIGS. 1, 2 and 4, container 11 is fixedly positionedand extends transverse a leading edge of photosensitive laminate 13whereby to effect unidirectional discharge of the containers contents 12between imagereceiving layer 24 and the stated layer next adjacentthereto, upon application of compressive force to container 11. Thus,container 11, as illustrated in FIG. 2, is fixedly positioned andextends transverse a leading edge of laminate 13 with its longitudinalmarginal seal 30 directed toward the interface between image-receivinglayer 24 and aux iliary layer 23. As shown in FIGS. 1, 2 and 4,container 11 is fixed secured to laminate 13 by extension 32 of tape 28extending over a portion of one wall 29 of the container, in combinationwith a separate retaining member such as illustrated retaining tape 33extending over a portion of the other wall 29 of the container and aportion of laminate 13s surface generally equal in area to about thatcovered by tape 28.

As illustrated in FIG. 6, extension flap 32 of tape 28 is preferably ofsuch area and dimensions that upon, for example, manual separation ofcontainer 11 and tape 33, subsequent to distribution of processingcomposition 12, from the remainder of film unit 10, flap 32 may befolded over the edge of laminate 13, previously covered by tape 33, inorder to facilitate maintenance of the laminates structural integrity,for example, during the fiexations inevitable in storage and use of theprocessed film unit, and to provide a suitable mask or frame, forviewing of the transfer image through the picture viewing area oftransparent layer 27.

The fluid contents of the container comprise an aqueous alkalinesolution, having a pH and solvent concentration at which the dyedevelopers are soluble and diflusible, which contains an opacifyingagent in a quantity sufficient to mask the dye developers associatedwith the silver halide emulsions subsequent to processing andadditionally contains a processing composition insoluble polymericdispersion adapted upon loss of processing composition solvent tocoalesce at ambient temperatures to provide a substantially continuous,dye impermeable polymeric layer.

In general, in a preferred embodiment the concentration of opacifyingagent or agents selected will be that SUlTlCifiIlt to prevent furtherexposure of the film units silver halide emulsion or emulsions, byactinic radiation traversing through the dimensionally stabletransparent layer, subsequent to distribution of the processing solutionintermediate the dyeable polymeric layer and the stated layer nextadjacent thereto. Accordingly, the film unit may be processed,subsequent to distribution of the composition, in the presence of suchradiation, in view of the fact that the silver halide emulsion oremulsions or the laminate are appropriately protected by incidentradiation, at one major surface by the opaque processing composition andat the remaining major surface by the dimensionally stable opaque layer.If the illustrated binder tapes are also opaque, edge leakage of actinicradiation incident on the emulsion or emulsions will also be prevented.The selected opacifying agent, however, should be one providing abackground suitable for viewing the dye developer transfer image formedin the dyeable polymeric layer. In general, while substantially anyopacifying agent may be employed, it is preferred that an opacifyingagent be selected that will not interfere with the color integrity ofthe dye transfer image, as viewed by the observer, and, most preferably,an agent which is aesthetically pleasing to the viewer and does notprovide a background noise signal degrading, or detracting from, theinformation content of the image. Particularly desirable opacifyingagents will be those providing a white background, for viewing thetransfer image, and specifically those conventionally employed toprovide background for reflection photographic prints and, especially,those agents possessing the optical properties desired for reflection ofincident radiation.

As examples of opacifying agents, mention may be made of barium sulfate,zinc oxide, titanium oxide, barium stearate, silver flake, silicates,alumina, zirconium oxide, zirconium acetyl acetate, sodium zirconiumsulfate, kaolin, mica, and the like.

-A particularly preferred agent comprises titanium dioxide due to itshighly effective reflection properties. In general, based upon percenttitanium dioxide (weight volume), a processing composition containingabout 40- 70 grams of titanium dioxide dispersed in 100 cc. of WaterWill provide a percent reflectance of about 8590%. In the most preferredembodiments, the percent reflectance particularly desired will be in theorder of above 85%.

Where it is desired to increase the radiation filtering capacity of aprocessing composition containing, for example, titanium dioxide or thelike, selected predominantly for its radiation reflecting properties,beyond that ordinarily obtained or required to obscure or mask the dyeand/ or developed silver associated with the photosensitive silverhalide emulsion layers, it may also be desirable to provide anadditional opacifying agent, exhibiting more effective filtration ofradiation incident on the transparent support layer during processing,such as carbon black, for example, added in a concentration of about onepart carbon black to 100 to 500 parts titanium dioxide, in order tofurther protect the emulsions from physical fog formation duringprocessing.

In general, the concentration of processing composition insolublepolymeric dispersion retained in the processing composition will be thatsufficient to provide, upon coalescence at ambient temperatures anddecrease of processing composition solvent, a substantially continuous,dye developer impermeable polymeric layer, subsequent to distribution ofthe processing composition between the dyeable polymeric layer and thestated layer next adjacent thereto.

As examples of processing composition insoluble polymeric materialsparticularly adapted for dispersion in a preselected processingcomposition and which will coalesce upon loss of processing compositionsolvent to provide a film at ambient temperatures, mention may be madeof the various polymeric solid and liquid materials which provide alatex when dispersed in a solvent in which they are insoluble and stableand, particularly when dispersed in Water possessing a preselected pH,known in the art to coalesce at ambient temperatures and at relativelyrapid rates upon loss of dispersent solvent to provide relativelyimpermeable substantially continuous films or polymeric layers includingbutadiene/ styrene copolymers; polyacrylamides; polymethylmethacrylates;polyvinyl chlorides and copolymers thereof; polyvinyl acetates andcopolymers thereof; acrylonitrile/ethyl acrylate copolyrners; acrylonitrile/styrene/butadiene terpolymers; and the like.

In general, the polymeric dispersion discontinuous phase dispersed in anaqueous continuous phase will comprise a concentration of polymerparticles adapted to provide a substantially continuous filmapproximately 5 to 30 microns in thickness upon coalescence subsequentto distribution and transpiration of processing composition solventWater content. For a substantially continuous layer possessing thegeneral dimensions of approximately 4 inches x 5 inches x 20 microns,such concentration will ordinarily be Within the range of about 5 to 40grams of particulate polymer/ cc. of processing composition Watercontent dependent upon specific polymer selected. Upon coalescence, thesubstantially continuous polymeric layer may contain entrained orentrapped therein one or more of the components, adjuvants or agentsoriginally retained by the processing composition or the like, such asopacifying agent initially distributed in the processing composition inthe preferred film unit embodiments detailed above.

In particularly preferred embodiments of the present invention, thesubstantially continuous polymeric film provided upon coalescence, inaddition to being impermeable to solubilized dye developer, will also besubstantially impermeable to solubilized photographic adjuncts, presentwithin the film unit, in general and more particularly those possessingphysical dimensions, for example, molecular size, less than that of dyedeveloper such as, for example, antifoggants, development restrainers,quaternary accelerators, emulsion stabilizers and sensitizers, and thelike, in order to still further enhance maintenance of dye transferimage stability and accuity.

In the performance of a diffusion transfer multicolor process employingfilm unit 10, the unit is exposed to radiation, actinic tophotosensitive laminate 13, incident on the laminates exposure surface34, as illustrated in FIG. 2.

Subsequent to exposure, as illustrated by FIGS. 2 and 4, film unit 10 isprocessed by being passed through opposed suitably gapped rolls 35 inorder to apply compressive pressure to frangible container 11 and toeffect rupture of longitudinal seal 30 and distribution of alkalineprocessing composition 12, having a pH and solvent concentration atwhich the cyan, magenta and yellow dye developers are soluble anddiffusible, intermediate dyeable polymeric layer 24 and auxiliary layer23.

Alkaline processing solution 12 permeates emulsion layers 16, 1% and 22to initiate development of the latent images contained in the respectiveemulsions. The cyan, magenta and yellow dye developers, of layers 15, 18and 21, are immobilized, as a function of the development of theirrespective associated silver halide emulsions, preferably substantiallyas a result of their conversion from the reduced form to theirrelatively insoluble and nondiifusible oxidized form, thereby providingimagewise distributions of mobile, soluble and difiusible cyan, magentaand yellow dye developer, as a function of the point-to-point degree oftheir associated emulsions exposure. At least part of the imagewisedistributions of mobile cyan, magenta and yellow dye developertransfers, by diffusion, to aqueous alkaline solution permeablepolymeric layer 24 to provide a multicolor dye transfer image to thatlayer. Subsequent to substantial transfer image formation, a sufiicientportion of the solvent comprising aqueous alkaline solution 12transfers, by osmotic diffusion, through vapor permeable, liquidimpermeable polymeric layers 14 and 27 whereby alkaline solution 12decreases in solvent concentration, as a function of diffusion andtranspiration, to a solvent concentration at which the processingcomposition insoluble polymeric dispersed phase coalesces to provide asubstantially continuous dye developer impermeable polymeric layer 25 toprovide thereby a stable multicolor dye transfer image.

Subsequent to distribution of processing solution 12, container 11 maybe manually dissociated from the remainder of the film unit, asdescribed above, to provide the product illustrated in FIG. 6.

The present invention will be further illustrated and detailed inconjunction with the following illustrative constructions which set outrepresentative embodiments and photographic utilization of the novelphotographic film units of this invention, which, however, are notlimited to the details therein set forth and are intended to beillustrative only.

Film units similar to that shown in the drawings may be prepared, forexample, by coating, in succession, on a gelatin subbed, 4 mil opaquepolyethylene terephthalate film base, the following layers:

(1) A layer of the cyan dye developer1,4-bis-(B-[hydroquinonyl-a-methyl] ethylamino)-5,8-dihydroxyanthraquinone dispersed in gelatin and coated at a coverage of about 150mgs./ft. of dye and about 200 mgs./ft. of gelatin;

(2) A red-sensitive gelatino-silver iodobromide emulsion coated at acoverage of about 200 mgs./ft. of silver and about 100 mgs./ft. ofgelatin;

(3) A layer of gelatin coated at a coverage of about 200 mgS./ft.

(4) A layer of the magenta dye developer Z-(p-[B-hydroquinonylethyl]phenylazo)-4-isopropoxy-1-naphthol dispersed in gelatin and coated at acoverage of 70 mgs./ ft. of dye and about 100 mgs./ft. of gelatin.

(5) A green sensitive gelatino silver iodobromide emulsion coated at acoverage of about 100 mgs./ft. of silver and 60 mgs./ft. of gelatin;

(6) A layer containing 4'-methylphenyl hydroquinone dispersed in gelatinand coated at coverage of about mgs./ft. of 4'-methylphenyl hydroquinoneand about 15 0 mgs./ft. of gelatin;

(7) A layer of the yellow dye developer 4-(p-[8-hydroquinonylethyl]-phenylazo) 3 (N nhexylcarboxamido)-1-phenyl-5-pyrazolone dispersed in gelatin and coatedat a coverage of about 40 mgs./ft. of dye and 50 mgs./ft. of gelatin;

(8) A blue-sensitive gelatino-silver iodobromide emulsion coated at acoverage of about 60 mgs./ft. of silver and about 50 mgs./ft. ofgelatin; and

(9) A layer of gelatin coated at a coverage of about mgs./ft. ofgelatin.

Then a transparent 4 mil. polyethylene terephthalate film base may becoated, in succession, with the following illustrative layers:

(1) The partial butyl ester of polyethylene/maleic anhydride copolymerprepared by refluxing, for 14 hours, 300 grams of high viscositypoly-(ethylene/maleic anhydride), 140 grams of n-butyl alcohol and 1 cc.of 85% phosphoric acid to provide a polymeric acid layer approx- 0imately 0.75 mil. thick;

(2) A 2:1 solution of hydroxypropyl cellulose and polyvinyl alcohol inwater to provide a polymeric spacer layer approximately 0.25 mil. thick;and

3) A 2:1 mixture, by weight, of polyvinyl alcohol andpoly-4-vinylpyridine, at a coverage of approximately 600 mgs./ft. toprovide a polymeric image-receiving layer approximately 0.40 mil. thick.

The two components thus prepared may then be taped together in laminateform, at their respective edges, by means of a pressure-sensitivebinding tape extending around, in contact with, and over the edges ofthe resultant laminate.

A rupturable container comprising an outer layer of lead foil and aninner liner or layer of polyvinyl chloride retaining an aqueous alkalineprocessing solution comprising:

Water: 100 cc.

Potassium hydroxide: 11.2 grams.

Hydroxyethyl cellulose (high viscosity) [commercially available fromHercules Powder Co., Wilmington, Del., under the trade name Natrasol250]: 3.4 grams.

N-benzyl-a-picolinium bromide: 1.5 grams.

Benzotriazole: 1.0 gram.

Titanium dioxide: 50.0 grams.

14 Carboxylated 5 COOH) styrene/butadiene copolymer [commerciallyavailable from W. R. Grace Co., New York, N.Y., under the trade nameDarex 526-L]: 20.0 grams.

may then be fixedly mounted on the leading edge, of each of thelaminates, by pressure-sensitive tapes interconnecting the respectivecontainers and laminates, such that upon application of compressivepressure to a container its contents would be distributed, upon ruptureof the containers marginal seal, between layer 9 and the polymericimage-receiving layer.

The photosensitive laminates may then be exposed through step wedges toselectively filtered radiation incident on the transparent polyethyleneterephthalate layer and initially processed, in the absence of actinicradiation, by passage of the exposed film unit through suitably gappedopposed rolls, to effect rupture of the container and distriubtion ofits contents. The multicolor dye transfer image formation may be viewedthrough the transparent polyethylene terephthalate film base and suchimage formation is found to be substantially completed and exhibitingthe required color brilliance, hues, saturation, stability andisolation, within a period of approximately 2 minutes.

The pH and solvent concentration of the processing solution initiallyemployed must be a pH at which the dye developers employed are solubleand diffusible. Although it has been found that the specific pH to beemployed may be readily determined empirically for any dye developer, orgroups of dye developers, most particularly desirable dye developers aresoluble at pHs above 9 and relatively insoluble at substantially anyalkaline pH, in oxidized form, and the system can be readily balancedaccordingly for such dye developers. In addition, although as previouslynoted, the processing composition, in the preferred embodiment, willinclude the stated film-forming viscosityincreasing agent, or agents, tofacilitate spreading of the composition and to facilitate maintenance ofthe spread composition as a structurally stable layer of the laminate,during distribution, it is not necessary that such agent be employed asa component of the composition.

Where desired, a polymeric acid layer, for example, of the typediscussed above, may be additionally incorporated, as stated, in thefilm unit of the present invention, to

provide reduction of the alkalinity of the processing solution from a pHat which the dyes are soluble to a pH at which the dyes aresubstantially nondilfusible, in order to advantageously furtherstabilize the dye transfer image. In such instance, the polymeric acidlayer may be positioned intermediate the transparent support andimage-receiving layer, and/ or the opaque support and next adjacentemulsion/dye unit layer, and the film unit may also contain a polymericspacer or barrier layer next adjacent the polymeric acid layer, oppositethe respective support layer, as previously described.

As disclosed in aforementioned U.S. Pat. No. 3,362,819, the presence ofan inert spacer layer Was found to be effective in evening out thevarious reaction rates over a wide range of temperatures, for example,by preventing premature pH reduction when imbibition is effected attemperatures above room temperature, for example, at to F. By providingan inert spacer layer, that application discloses that the rate at whichalkali is available for capture in the polymeric acid layer becomes afunction of the alkali diffusion rates.

However, as disclosed in copending U.S. Patent application Ser. No.664,503, filed Aug. 30, 1967 and now 'U.S. Pat. No. 3,455,686 in thenames of Leonard C. Farney, Howard G. Rogers and Richard W. Young,preferably the aforementioned rate at which the cations of the alkalineprocessing composition, i.e., alkali ions, are available for capture inthe polymeric acid layer should be decreased with increasing transferprocessing temperatures in order to provide diffusion transfer colorprocesses relatively independent of positive transfer image variationsover an extended range of ambient temperatures.

Specifically, it is there stated to have been found that the diffusionrate of alkali through a permeable inert polymeric spacer layerincreases with increased processing temperature to the extent, forexample, that at relatively high transfer processing temperatures, thatis, transfer processing temperatures above approximately 80 F., apremature decrease in the pH of the transfer processing compositionoccurs due, at least in part, to the rapid diffusion of alkali from thedye transfer environment and its subsequent neutralization upon contactwith the polymeric acid layer. This was stated to be especially true ofalkali traversing an inert spacer layer possessing permeability toalkali optimized to be effected within the temperature range of optimumtransfer processing. Conversely, at temperatures below the optimumtransfer processing range, for example, temperatures below approximately40 F., the last-mentioned inert spacer layer was disclosed to provide aneffective diffusion barrier timewise preventing effective traverse ofthe inert spacer layer by alkali having temperature depressed diffusionrates and to result in maintenance of the transfer processingenvironments high pH for such an extended time interval as to facilitateformation of transfer image stain and its resultant degradation of thepositive transfer images color definition.

It is further stated in the last-mentioned copending application Ser.No. 664,503 to have been found, however, that if the inert spacer layerof the print-receiving element is replaced by a spacer layer whichcomprises a permeable polymeric layer exhibiting permeability inverselydependent on temperature, that is, a polymeric film-forming materialwhich exhibits decreasing permeability to solubilized alkali derivedcations such as alkali metal and quaternary ammonium ions underconditions of increasing temperature, that the positive transfer imagedefects resultant from the aforementioned overexended pH maintenanceand/ or premature pH reduction are obviated.

As examples of polymers which were disclosed to exhibit inversetemperature-dependent permeability to alkali, mention may be made of:hydroxypropyl polyvinyl alcohol, polyvinyl methyl ether, polyethyleneoxide, polyvinyl oxazolidone, hydroxypropyl methyl cellulose, iospropylcellulose, partial acetals of polyvinyl alcohol such as partialpolyvinyl butyral, partial polyvinyl formal, partial polyvinyl acetal,partial polyvinyl propional, and the like.

The last-mentioned specified acetals of polyvinyl were stated togenerally comprise saturated aliphatic hydrocarbon chains of a molecularweight of at least l000, preferably of about 1000 to 50,000, possessinga degree of acetalatiou Within about 10 to 10 to 30%, 20 to 80%, and 10to 40%, of the polyvinyl alcohols theoretical polymeric hydroxy groups,respectively, and including mixed acetals where desired.

Where desired, a mixture of the polymers is to be employed, for example,a mixture of hydroxypropyl methyl cellulose and partial polyvinylbutyral.

Employment of the detailed and preferred film units of the presentinvention, according to the herein described color diffusion transferprocess, specifically provides for the production of a highly stable dyetransfer image accomplished, at least in part, by effectively obviatingthe previously discussed disadvantages of the prior art prodnets andprocesses, by in situ generation of a substantially continuous, dyeimage-forming material impermeable polymeric layer or stratumintermediate the dye imagecarrying layer and the photosensitive silverhalide emulsion and associated dye image-forming material layers of thefilm unit, subsequent to substantial dye transfer image formation. Thestable dye transfer image is obtained irrespective of the fact that thefilm unit is maintained as an integral laminate unit during exposure,processing, viewing and storage of the unit, and undesired dyeimageforming material transfer, of the type previously discussed indetail, subsequent to substantial dye transfer image formation, iseffectively prevented by the in situ generated physical barrierpolymeric layer. Accordingly, by means of the present invention,multicolor dye transfer images may be provided which exhibit desiredmaximum and minimum dye transfer image densities; yellow, magenta andcyan dye saturation; red, green and blue hues; and color separation.These unexpected advantages are in addition to the manufacturingadvantages obtained by reason of the present inventions integral colortransfer film unit and which will be readily apparent from examinationof the units parameters, that is, for example, advantages in moreefficient utilization of fabricating materials and components, enhancedsimplicity of film manufacture and camera design and construction, andmore simplified and effectively controlled customer utilization of theunit.

The dimensionally stable support layers referred to may comprise any ofthe various types of conventional opaque and transparent rigid orflexible materials possessing the requisite liquid impermeability andvapor transmissivity denoted above, and may comprise polymeric films ofboth synthetic types and those derived from naturally occurringproducts. Particularly suitable materials include aqueous alkalinesolution impermeable, water vapor permeable, flexible polymericmaterials such as vapor permeable polymeric films derived from ethyleneglycol terephthalic acid, vinyl chloride polymers; polyvinyl acetate;polyamides; polymethacrylic acid methyl and ethyl esters; cellulosederivatives such as cellulose, acetate, triacetate, nitrate, propionate,butyrate acetateproprionate, or acetate-butyrate; alkaline solutionimpermeable, water vapor permeable papers; crosslinked polyvinylalcohol; regenerated cellulose; and the like.

It will be noted that the liquid processing composition employed maycontain an auxiliary or accelerating developing agent, such asp-methylamino'phenol, 2,4-diaminophenol, p-benzylaminophenyl,hydroquinone, toluhydroquinone, phenylhydroquinone,4-methylphenylhydroquinone, etc. It is also contemplated to employ aplurality of auxiliary or accelerating developing agents, such as a3-pyrazolidone developing agent and a benzenoid developing agent, asdisclosed in U.S. Pat. No. 3,039,869, issued June 19, 1962. As examplesof suitable combinations of auxiliary developing agents, mention may bemade of 1-phenyl-3-pyrazolidone in combination with p-benzylaminophenoland 1-phenyl-3-pyrazolidone in combination with2,5-bis-ethylenimino-hydro quinone. Such auxiliary developing agents maybe employed in the liquid processing composition or they may beinitially incorporated, at least in part, in any one or more of thesilver halide emulsion strata, the strata containing the dye developers,the interlayers, the overcoat layer, the image-receiving layer, or inany other auxiliary layer, or layers, of the film unit. It may be notedthat at least a portion of the dye developer oxidized during developmentmay be oxidized and immobilized as a result of a reaction, e.g., anenergy-transfer reaction, with the oxidation product of an oxidizedauxiliary developing agent, the latter developing agent being oxidizedby the development of exposed silver halide. Such a reaction of oxidizeddeveloping agent With unoxidized dye developer would regenerate theauxiliary developing agent for further reaction with the exposed silverhalide.

In addition, development may be effected in the presence of an oniumcompound, particularly a quaternary ammonium compound, in accordancewith the processes disclosed in U.S. Pat. No. 3,173,786, issued Mar. 16,1965.

It will be apparent that the relative proportions of the agents of thediffusion transfer processing composition may be altered to suit therequirements of the operator. Thus, it is within the scope of thisinvention to modify the herein described developing compositions by thesubstitution of preservatives, alkalies, etc., other than thosespecifically mentioned, provided that the pH of the composition isinitially at the first pH and solvent concentration require. Whendesirable, it is also contemplated to include, in the developingcomposition, compo nents such as restrainers, accelerators, etc.Similarly, the concentration of various components may be varied over awide range and when desirable adaptable components may be disposed inthe photosensitive element, prior to exposure, in a separate permeablelayer of the photosensitive element and/or in the photosensitiveemulsion.

In all examples of this specification, percentages of components aregiven by weight unless otherwise indicated.

An extensive compilation of specific dye developers particularly adaptedfor employment in photographic diffusion transfer processes is set forthin aforementioned U.S. Pat. No. 2,983,606 and in the various copendingU.S. applications referred to in that patent, especially in the table ofU.S. applications incorporated by reference into the patent as detailedin column 27. An examples of additional U.S. patents detailing specificdye developers for photographic transfer process use, mention may alsobe made of U.S. Pats. Nos. 2,983,605; 2,992,106; 3,047,386; 3,076,808;3,076,820; 3,077,402; 3,126,280; 3,131,061; 3,134,762; 3,134,765;3,135,604; 3,135,605; 3,135,606; 3,135,734; 3,141,772; 3,142,565; andthe like.

As additional examples of synthetic, film-forming, permeable polymersparticularly adapted to retain dispersed dye developer, mention may bemade of nitrocarboxymethyl cellulose, as disclosed in U.S. Pat. No.2,992,104; an acylamidobenzene sulfo ester of a partial sulfobenzal ofpolyvinyl alcohol, as discolsed in U.S. Pat. No. 3,043,692; polymers ofN-alkyl-u,Bunsatr1rated carboxamides and copolymers ofN-alkyl-ot,[3-carboxamides with N-hydroxyalkyl-a,,8-unsaturatedcarboxamides, as disclosed in U.S. Pat. No. 3,069,263; copolymers ofvinylphthalimide and O S-unsaturated carboxylic acids, as disclosed inU.S. Pat. No. 3,061,428; copolymers of N-vinylpyrrolidones andu,fi-unsaturated carboxylic acids and terpolymers ofN-vinylpyrrolidones, :,{3-111'1831Uf818d carboxylic acids and alkylesters of a s-unsaturated carboxyic acids, as disclosed in U.S. Pat. No.3,044,873; copolymers of N,N-dialkyl-OMS-unsaturated carboxamides witha,5-unsaturated carboxylic acids, the corresponding amides of suchacids, and copolymers of N-aryland N- cycloalkyl-u,,8-unsaturatedcarboxamides with 0:,[3-1111881- urated carboxylic acids, as disclosedin U.S. Pat. No. 3,069,264; and the like.

In addition to conventional techniques for the direct dispersion of aparticulate solid material in a polymeric, or colloidal, matrix such asball-milling and the lik techniques, the preparation of the dyedeveloper dispersion may also be obtained by dissolving the dye in anappropriate solvent, or mixture of solvents, and the resultant solutiondistributed in the polymeric binder, with optional subsequent removal ofthe solvent, or solvents, employed, as, for example, by vaporizationWhere the selected solvent, or solvents, possesses a sufiiciently lowboiling point or washing where the selected solvent, or solvents,possesses a sufiiciently high differential solubility in the washmedium, for example, water, when measured against the solubility of theremaining composition components, and/or obtained by dissolving both thepolymeric binder and dye in a common solvent.

For further detailed treatment of solvent distribution systems of thetypes referred to above, and for an extensive compilation of theconventional solvents traditionally employed in the art to effectdistribution of photographic color-providing materials in polymericbinders, specifically for the formation component layers of photographicfilm units, reference may be made to U.S. Pats.

18 Nos. 2,269,158; 2,322,027; 2,304,939; 2,304,940; 2,801,- 171; and thelike.

Although the invention has been discussed in detail throughout employingdye developers, the preferred dye image-providing materials, it will bereadily recognized that other, less preferred, dye image-providingmaterials may be substituted in replacement of the preferred dyedevelopers in the practice of the invention. For example, there may beemployed dye image-forming materials such as those dsiclosed in U.S.Pats. Nos. 2,647,049, issued July 28, 1953; 2,6661,293, issued Dec. 1,1953; 2,698,244, issued Dec. 28, 1954; 2,698,788, issued Jan. 4, 1955;and 2,802,735, issued Aug. 13, 1957, wherein color diffusion transferprocesses are described which employ color coupling techniquescomprising, at least in part, reacting one or more color developingagents and one or more color formers or couplers to provide a dyetransfer image to a superposed image-receiving layer and those disclosedin U.S. Pat. No. 2,774,668, issued Dec. 18, 1956, wherein colordiffusion transfer processes are described which employ the imagewisedifferential transfer of complete dyes by the mechanisms thereindescribed to provide a transfer dye image to a contiguousimage-receiving layer.

For the production of the photosensitive gelatino silver halideemulsions employed to provide the film unit, the silver halide crystalsmay be prepared by reacting a water-soluble silver salt, such as silvernitrate, with at least one water-soluble halide, such as ammonium,potassium or sodium bromide, preferably together with a correspondingiodide, in an aqueous solution of a peptizing agent such as a colloidalgelatin solution; digesting the dispersion at an elevated temperature,to provide increased crystal growth; washing the resultant dispersion toremove undesirable reaction products and residual water-soluble salts bychilling the dispersion, noodling the set dispersion, and washing thenoodles with cold water, or alternatively, employing any of the various1100 systems, or procedures, adapted to effect removal of undesiredcomponents, for example, the procedures described in U.S. Pats. Nos.2,614,928; 2,614,929; 2,728,662; and the like; after-ripening thedispersion at an elevated temperature in combination with the additionof gelatin and various adjuncts, for example, chemical sensitizingagents of U.S. Pats. Nos. 1,574,944; 1,623,499; 2,410,689; 2,597,856;2,597,915; 2,487,850; 2,518,698; 2,521,926; and the like; all accordingto the traditional procedures of the art as described in Neblette, C.B., Photography, Its Materials and Processes, 6th ed., 1962.

Optical sensitization of the emulsions silver halide crystals may beaccomplished by contact of the emulsion composition with an effectiveconcentration of the selected optical sensitizing dyes dissolved in anappropriate dispersing solvent such as methanol, ethanol, acetone,water, and the like; all according to the traditional procedures of theart, as described in Hammer, F. M., The Cyanine Dyes and RelatedCompounds.

Additional optional additives, such as coating aids, hardeners,viscosity-increasing agents, stabilizers, preservatives, and the like,for example, those set forth hereinafter, also may be incorporated inthe emulsion formulation, according to the conventional procedures knownin the photographic emulsion manufacturing art.

The photoresponsive material of the photographic emulsion will, aspreviously described, preferably comprise a crystal of silver, forexample, one or more of the silver halides such as silver chloride,silver iodide, silver bromide, or mixed silver halides such as silverchlorobromide or silver iodobromide, of varying halide ratios andvarying silver concentrations.

The emulsions may include the various adjuncts, or addenda, according tothe techniques disclosed in the art.

As the binder for the respective emulsion strata, the aforementionedgelatin may be, in whole or in part, re-

placed with some other colloidal material such as albumin; casein; orzein; or resins such as cellulose derivatives, as described in US. Pats.Nos. 2,322,085, and 2,327,808; polyacrylamides, as described in US. Pat.No. 2,541,474; vinyl polymers such as described in an extensivemultiplicity of readily available US. and foreign patents.

Although the preceding description of the invention has been couched interms of the preferred photosensitive component construction wherein atleast two selectively sensitized photosensitive strata are in contiguouscoplanar relationship and, specifically, in terms of the preferredtripack type structure comprising a red-sensitive silver halide emulsionstratum, a green-sensitive silver halide emulsion stratum and ablue-sensitive silver halide emulsion stratum having associatedtherewith, respectively, a cyan dye developer, a magenta dye developerand a yellow dye developer, the photosensitive component of the filmunit may comprise at least two sets of selectively sensitized minutephotosensitive elements arranged in the form of a photosensitive screenwherein each of the minute photosensitive elements has associatedtherewith, for example, an appropriate dye developer in or behind itsrespective silver halide emulsion portion. In general, a suitablephotosensitive screen will comprise minute red-sensitized emulsionelements, minute green-sensitized emulsion elements and minuteblue-sensitized emulsion elements arranged in side-by-side relationshipin a screen pattern and having associated therewith, respectively, acyan, a magenta and a yellow dye developer.

The present invention also includes the employment of a black dyedeveloper and the use of a mixture of dye developers adapted to providea black and white transfer image, for example, the employment of dyedevelopers of the three subtractive colors in an appropriate mixture inwhich the quantities of the dye developers are proportioned such thatthe colors combine to provide black.

Where in the specification, the expression positive image has been used,this expression should not be interpreted in a restrictive sense sinceit is used primarily for purposes of illustration, in that it definesthe image produced on the image-carrying layer as being reversed, in thepositive-negative sense, with respect to the image in the photosensitiveemulsion layers. As an example of an alternative meaning for positiveimage, assume that the photosensitive element is exposed to actiniclight through a negative transparency. In this case, the latent image inthe photosensitive emulsion layers will be a positive and the dye imageproduced on the image-carrying layer will be a negative. The expressionpositive image is intended to cover such an image produced on theimage-carrying layer.

It will be recognized that, by reason of the preferred film unitsstructural parameters, the transfer image formed upon direct exposure ofthe film unit to a selected subject and processing, will be ageometrically reversed image of the subject. Accordingly, to providetransfer image formation geometrically nonreversed, exposure of suchfilm unit should be accomplished through an image re versing opticalsystem such a camera possessing an image reversing optical system.

In addition to the described essential layers, it will be recognizedthat the film unit may also contain one or more subcoats or layers,which, in turn, may contain one or more additives such as plasticizers,intermediate essential layers for the purpose, for example, of improvingadhesion, and that any one or more of the described layers may comprisea composite of two or more strata of same, or different, components andwhich may be contiguous, or separated from, each other, for example, twoor more neutralizing layers or the like, one of which may be disposedintermediate the cyan dye imageforming component retaining layer and thedimensionally stable opaque layer.

Since certain changes may be made in the above product and processwithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:

1. A photographic film unit which is adapted to be processed by passingsaid unit between a pair of juxtaposed pressure-applying members andwhich comprises, in combination:

a photosensitive element comprising a composite structure containing, asessential layers, in sequence, a first dimensionally stable layer opaqueto incident actinic radiation; a photosensitive silver halide emulsionlayer having associated therewith a dye image-forming material which isprocessing composition soluble and diflusibie as a function of exposureof the photosensitive silver halide emulsion layer to incident actinicradiation; a polymeric layer dyeable by said dye image-providingmaterial; a second dimensionally stable layer transparent to incidentactinic radiation; and means securing said layers in substantially fixedrelationship; and

a rupturable container retaining a processing composition containing anopacifying agent in a quantity sufficient to mask said dyeimage-providing material and a processing composition insolublepolymeric dispersion adapted upon loss of processing composition solventto coalesce at ambient temperatures, fixedly positioned and extendingtransverse a leading edge of said photosensitive element to effectunidirectional discharge of said containers processing compositionbetween said dyeable polymeric layer and the photo sensitive silverhalide emulsion layer next adjacent thereto, said polymeric dispersionpresent in a quantity sufiicient upon coalescence to provide a dyeimage-forming material impermeable polymeric layer disposed intermediatesaid dyeable polymeric layer and the photosensitive silver halideemulsion layer next adjacent thereto.

2. A photographic film unit as defined in claim 1 wherein said firstdimensionally stable layer is transparent to incident actinic radiation.

3. A photographic film unit as defined in claim 2 wherein saidopacifying agent is initially present intermediate said dyeablepolymeric layer and the photosensitive silver halide emulsion layer nextadjacent thereto in a quantity suflicient to mask said dyeimage-providing material.

4. A photographic film unit as defined in claim 1 wherein saidcomposition is an aqueous alkaline composition.

5. A photographic film unit as defined in claim 4 wherein said dyeimage-providing material is a dye which is a silver halide developingagent.

6. A photographic film unit as defined in claim 1 wherein saidopacifying agent is present in a quentity suflicient to prevent exposureof said silver halide emulsion during processing in the presence ofradiation actinic thereto and incident on said distributed processingsolution.

7. A photographic film unit as defined in claim 1 wherein saidopacifying agent is actinic radiation reflective.

8. A photographic film unit as defined in claim 7 wherein saidopacifying agent is titanium dioxide.

9. A photographic film unit as defined in claim 5 wherein saidphotosensitive element comprises at least two selectively sensitizedsilver halide emulsion layers each having a dye which dye is a silverhalide developing agent of predetermined color associated therewith,each of said dyes soluble and diifusible in alkaline processingcomposition as a function of the point-to-point degree of exposure ofthe respective emulsion associated therewith.

10. A photographic film unit as defined in claim 9' wherein each of saidselectively sensitized photosensitive silver halide emulsions haspredominant spectral sensitivity to separate regions of the spectrum andthe dye associ ated with each of said silver halide emulsion layerspossesses a spectral absorption range subsequent to processingsubstantially complementary to the predominant sensitivity range of itsassociated emulsion layer.

11. A photographic film unit as defined in claim 10 wherein each of saidsilver halide emulsion layers and its associated dye is separated fromthe next adjacent silver halide emulsion layer and its associated dye byan alkaline solution permeable polymeric interlayer.

12. A photographic film unit as defined in claim including at least onepolymeric acid layer positioned intermediate at least one of said firstdimensionally stable layers and the photosensitive silver halideemulsion layer next adjacent thereto, and said second dimensionallystable layer and the dyeable polymeric layer next adjacent thereto.

13. A photographic film unit as defined in claim 12 wherein saidpolymeric acidic layer contains sufiicient acidifying groups to effectreduction of said processing composition from a first pH at which saiddye is substantially soluble and diffusible to a second pH at which saiddye is substantially nondiffusible.

14. A photographic film unit as defined in claim 5 wherein saidprocessing composition insoluble polymeric dispersion comprisescarboxylated styrene/butadiene copolymer.

15. A photographic film unit as defined in claim 14 wherein saidprocessing composition insoluble polymeric dispersion is present in aquantity sufficient to provide upon distribution intermediate saiddyeable polymeric layer and the silver halide emulsion layer nextadjacent thereto and coalescence upon loss of dispersant solvent a dyeimpermeable polymeric layer within the range of about 5 to 30 microns inthickness.

16. A photographic film unit as defined in claim 15 wherein saidprocessing composition insoluble polymeric dispersion is present in aconcentration of about 5 to 40 g. of polymer/ 100 cc. of processingcomposition water.

17. A photographic film unit as defined in claim which is adapted to beprocessed by passing said unit between a pair of juxtaposedpressure-applying members and which comprises, in combination, acomposite structure containing, as essential layers, in sequence, adimensionally stable, liquid impermeable opaque layer; an alkalinesolution permeable polymeric layer containing cyan dye; a red-sensitivesilver halide emulsion layer; an alkaline solution permeable polymericlayer containing magenta dye; a green-sensitive silver halide emulsionlayer; an alkaline solution permeable polymeric layer containing yellowdye; a blue-sensitive silver halide emulsion layer, each of said cyan,magenta and yellow dyes being silver halide developing agents and beingsoluble and ditfusible, in an aqueous alkaline solution at a first pH;an alkaline solution permeable transparent polymeric layer dyeable bysaid dyes; an alkaline solution permeable transparent polymeric acidiclayer containing sufiicient acidifying groups to effect reduction of aprocessing solution having said first pH to a second pH at which saiddyes are substantially nondiffusible; a dimensionally stable, liquidimpermeable transparent layer; and means securing said layers insubstantially fixed relationship; and

a rupturable container retaining an aqueous alkaline processingcomposition possessing said first pH and an opacifying agent in aquantity sufficient to mask said dyes and a processing compositioninsoluble particulate polymeric dispersion adapted upon tranpiration ofprocessing composition water content to coalesce at ambienttemperatures, fixedly positioned and extending transverse a leading edgeof said photosensitive element to effect unidirectional discharge ofsaid containers processing composition between said dyeable polymericlayer and said blue-sensitive silver halide emulsion layer uponapplication of compressive forces to said container, said polymericdispersion present in a quantity sufficient upon coalescence to providea substantially continuous dye impermeable polymeric layer intermediatesaid dyeable polymeric layer and said blue-sensitive silver halideemulsion layer.

18. A photographic film unit as defined in claim 17 wherein said firstpH is above 9 and said second pH is below 9.

19. A photographtic film unit as defined in claim 18 wherein saidopacifying agent is actinic radiation reflective.

20. A photographic film unit as defined in claim 19 wherein saidopacifying agent is titanium dioxide.

21. A photographic film unit as defined in claim 20 wherein saidprocessing composition insoluble polymeric dispersion comprisescarboxylated styrene-butadiene copolymer.

22. A photographic film unit as defined in claim 21 wherein saidprocessing composition insoluble polymeric dispersion is present in aconcentration of about 5 to 40 g. of polymer/ cc. of processingcomposition water.

23. A process for forming transfer images in color which comprises, incombination, the steps of (a) exposing a photographic film unit which isadapted to be processed by passing the unit between a pair of juxtaposedpressure-applying members and which includes, in combination, acomposite structure comprising a first dimensionally stable layer opaqueto incident actinic radiation; a photosensitive silver halide emulsionlayer having associated therewith a dye image-forming material which isprocessing composition soluble and diflfusible as a function of exposureof the photosensitive silver halide emulsion layer to incident actinicradiation; a polymeric layer dyeable by said dye image-providingmaterial; a second dimensionally stable layer transparent to incidentactinic radiation; and means securing said layers in substantially fixedrelationship; and

a rupturable container retaining a processing composition containing anopacifying agent in a quantity sufficient to mask said dyeimage-providing material and a processing composition insolublepolymeric dispersion adapted upon loss of processing composition solventto coalesce at ambient temperatures, fixedly positioned and extendingtransverse a leading edge of said photosensitive element to elfectunidirectional discharge of said containers processing compositionbetween said dyeable polymeric layer and the photosensitive silverhalide emulsion layer next adjacent thereto upon application ofcompressive force to said container, said polymeric dispersion presentin a quantity sufiicient upon coalescence to provide a dye image-formingmaterial impermeable polymeric layer disposed intermediate said dyeablepolymeric layer and the photosensitive silver halide emulsion nextadjacent thereto;

(b) applying compressive force to said rupturable container to elTectunidirectional discharge of said containers processing compositionbetween said dyeable polymeric layer and the photosensitive silverhalide emulsion layer next adjacent thereto;

(c) eifecting thereby development of said silver halide emulsion andforming, as a result of said development, an imagewise distribution ofmobile dye image-providing material as a function of the pointto-pointdegree of emulsion exposure;

(d) transferring, by diffusion, at least a portion of said imagewisedistribution of said mobile dye imageproviding material to saidpolymeric layer dyeable by said dye image-forming material to provide adye image thereto in terms of said distribution;

(e) transferring, by osmotic transpiration of processing compositionsolvent from said composite structure, subsequent to substantial dyetransfer image formation and preceding substantial environmental dyetransfer image degradation, a sutficient portion of the solvent of saidprocessing composition to thereby reduce said solvent concentrationintermediate said dyeable polymeric layer and said silver halideemulsion layer next adjacent to a concentration at which said processingcomposition insoluble polymeric dispersion coalesces at ambienttemperatures;

(f) coalescing said processing composition insoluble polymericdispersion as a result of said osmotic transpiration of processingcomposition solvent;

(g) forming thereby a dye image-forming material impermeable polymericlayer disposed intermediate said dyeable polymeric layer and the silverhalide emulsion next adjacent thereto; and

(h) maintaining said composite structure intact subsequent to saidprocessing.

24. A process as defined in claim 23 wherein said first dimensionallystable layer is transparent to actinic radiation.

25. A process as defined in claim 24 wherein said opacifying agent isinitially present intermediate said dyeable polymeric layer and thephotosensitive silver halide emulsion layer next adjacent thereto.

26. A process as defined in claim 23 wherein said solvent is water.

27. A process as defined in claim 26 wherein said dye image-providingmaterial is a dye which is a silver halide developing agent.

28. A process as defined in claim 27 wherein said opacifying agent ispresent in a quantity sufiicient to prevent exposure of said silverhalide emulsion during processing in the present of radiation actinicthereto and incident on said processing solution distributed betweensaid dyeable polymeric layer and said silver halide emulsion layer nextadjacent thereto.

29. A process as defined in claim 27 wherein said opacifying agent isactinic radiation reflective.

30. A process as defined in claim 29 wherein said opacifying agent istitanium dioxide.

31. A process as defined in claim 26 wherein said processing compositioninsoluble polymeric dispersion comprises carboxylated styrene/butadienecopolymer.

32. A process as defined in claim 26 wherein said processing compositioninsoluble polymeric dispersion is present in a quantity sufiicient toprovide upon distribution intermediate said dyeable polymeric layer andthe silver halide emulsion layer next adjacent thereto and coalesces adye image-forming material polymeric layer possessing a thickness withinthe range of about to 30 microns.

33. A process as defined in claim 32 wherein said processing compositioninsoluble polymeric dispersion is present in a concentration of about 5to g. of polymer/ 100 cc. of processing composition water.

34. A process as defined in claim 23 including the step of separatingsaid container from said composite structure subsequent to substantialtransfer image formation.

35. A process as defined in claim 27 which comprises, in combination,the steps of (a) exposing a photographic film unit which is adapted tobe processed by passage through a pair of juxtaposed pressure-applyingmembers and which includes in combination, a composite structurecomprising a first dimensionally stable, liquid impermeable layer opaqueto incident actinic radiation at least two selectively sensitized silverhalide emulsion layers, each of said silver halide emulsions havingassociated therewith a dye, which is a silver halide developing agent,of predetermined color, and is soluble and diffusible, in aqueousalkaline processing composition as a function of the point-to-pointdegree of exposure of the respective emulsions associated therewith; apolymeric layer dyeable by said dye; a second dimensionally stable,liquid impermeable layer transparent to incident actinic radiation; andmeans securing said layers in substantially fixed relationship; and

a rupturable container retaining an aqueous alkaline processingcomposition containing an opacifying agent in a quantity sufiicient tomask said dyes and an aqueous alkaline processing composition insolublepolymeric dispersion adapted upon loss of processing composition watercontent to coalesce at ambient temperatures, fixedly positioned andextending transverse a leading edge of said photosensitive element toeffect discharge of said containers aqueous alkaline processingcomposition between said dyeable polymeric layer and the photosensitivesilver halide emulsion layer next adjacent thereto upon application ofcompressive force to said container, said polymeric dispersion presentin a quantity suflicient upon coalescence to provide a dye impermeablepolymeric layer disposed intermediate said dyeable polymeric layer andthe photosensitive silver halide emulsion layer next adjacent thereto;

(b) applying compressive force to said rupturable container to effectdischarge of said containers aqueous alkaline processing compositionbetween said dyeable polymeric layer and the photosensitive silverhalide emulsion layer next adjacent thereto;

(c) effecting thereby development of each of said silver halideemulsions;

(d) immobilizing the dye associated with each of said emulsion layers asa result of development;

(c) forming thereby an imagewise distribution of mobile dye as afunction of the point-to-point degree of emulsion exposure;

(f) transferring, by imbibition, at least a portion of each of saidimagewise distributions of mobile dyes to said polymeric layer dyeableby said dyes to provide thereto a dye image;

(g) transferring, by osmotic transmission of aqueous alkaline processingcomposition solvent from said composite structure, subsequent tosubstantial dye transfer image formation and preceding said substantialenvironmental dye transfer image degradation, a sufiicient portion ofthe aqueous solvent of said aqueous alkaline processing composition tothereby reduce said solvent concentration intermediate said dyeablepolymeric layer and said silver halide emulsion layer next adjacent to aconcentration at which said aqueous alkaline processing compositioninsoluble polymeric dispersion coalesces at ambient temperatures;

(h) coalescing said aqueous alkaline processing composition insolublepolymeric dispersion as a result of said osmotic transpiration ofaqueous solvent;

(i) forming thereby a dye impermeable polymeric layer disposedintermediate said dyeable polymeric layer and the silver halide emulsionnext adjacent thereto;and

(j) maintaining said composite structure intact subsequent to saidprocessing.

36. A process as defined in claim 35 wherein each of said selectivelysensitized silver halide emulsion layers possess predominant spectralsensitivity to a separate region of the spectrum and the dye associatedwith each of said emulsion layers possesses a spectral absorption rangesubsequent to processing substantially complementary to the predominantsensitivity range of its associated emulsion.

37. A process as defined in claim 36 wherein said composite structureincludes at least one polymeric acid layer positioned intermediate atleast one of said first dimensionally stable layers and the nextadjacent photosensitive silver halide layer, aud said seconddimensionally stable layer and the next adjacent dyeable polymeric layerand said polymeric acid layers containing sufiicient acidifying groupsto effect reduction of an aqueous alkaline processing compositionpossessing a first pH at which said dyes are substantially soluble anddiffusible to a second pH at which said dyes are substantially nondif-25 fusible and including the step of transferring, by diffusion,subsequent to substantial transfer image formation, a sufficient portionof the ions of said alkaline processing solution to said polymeric acidlayers to thereby reduce the alkalinity of said solution from said firstpH to said second pH.

38. A process of forming transfer images in color as defined in claim 37which comprises, in combination, the steps of:

(a) exposing a photographic film unit which is adapted to be processedby passing said unit between a pair of juxtaposed pressure-applyingmembers and which includes, in combination, a photosensitive elementcomprising a laminate containing, as essential layers, in sequence, adimensionally stable alkaline solution impermeable opaque layer; ared-sensitive silver halide emulsion layer having associated therewithcyan dye; a green-sensitive silver halide emulsion layer havingassociated therewith magenta dye; a

blue-sensitive silver halide emulsion layer having associated therewithyellow dye; each of said cyan, magenta and yellow dyes being silverhalide developing agents and soluble and diffusible in aqueous alkalinesolution at a first pH; an alkaline solution permeable transparentpolymeric layer dyeable by said dyes; an alkaline solution permeabletransparent polymeric acid layer containing sufficient acidifying groupsto effect reduction of an alkaline processing solution having said firstpH to a second pH at Which said dyes are substantially insoluble andnondiffusible; a dimensionally stable, alkaline solution impermeabletransparent layer; and

a rupturable container retaining an aqueous alkaline processing solutionpossessing said first pH, an opacifying agent in a quantity sufficientto mask said dyes and an aqueous alkaline solution insoluble particulatepolymeric dispersion adapted upon loss of processing solution water tocoalesce at ambient temperatures, fixedly positioned and extendingtransverse a leading edge of said photosensitive element to effectunidirectional discharge of said containers processing solution betweensaid dyeable polymeric layer and said blue-sensitive silver halideemulsion layer upon application of compressive force to said container,said exposure effected by actinic radiation incident on saiddimensionally stable transparent layer, said polymeric dispersionpresent in a quantity sufficient upon coalescence to provide asubstantially continuous dye impermeable polymeric layer disposedintermediate said dyeable polymeric layer and said bluesensitive silverhalide emulsion layer;

(b) applying compressive force to said rupturable container to effectunidirectional discharge of said containers alkaline solution betweensaid alkaline solution permeable and dyeable polymeric layer and saidblue-sensitive silver halide emulsion layer;

(c) effecting thereby development of the latent image contained in eachof said red, green and blue-sensitive silver halide emulsions;

(d) immobilizing said yellow, magenta and cyan dye as a result ofdevelopment of their respective associated silver halide emulsions;

(e) forming thereby an imagewise distribution of immobile yellow,magenta and cyan dyes as a function 26 of the point-to-point degree ofexposure of their respective associated silver halide emulsions;

('f) transferring, by diffusion, at least a portion of each of saidimagewise distributions of mobile dye to said alkaline solutionpermeable polymeric layer dyeable by said dyes to provide thereto amulticolor dye image;

(g) transferring, by diffusion, subsequent to substantial transfer imageformation, a sufficient portion of the ions of said aqueous alkalinesolution to said alkaline solution permeable polymeric acid layer tothereby reduce the alkalinity of said solution from said first pH atwhich said dyes are soluble and diffusible to said second pH at whichsaid dyes are substantially nondiffusible;

(h) transferring, by diffusion, subsequent to substantial transfer imageformation and preceding substantial environmental transfer imagedegradation, from said laminate to the atmosphere a sufficient portionof the water of the alkaline processing solution to thereby reduce saidwater concentration intermediate said dyeable polymeric layer and saidblue-sensitive silver halide emulsion layer to a concentration at whichsaid aqueous alkaline processing solution insoluble polymeric dispersioncoalesces at ambient temperatures;

(i) coalescing said aqueous alkaline processing solution insolublepolymeric dispersion as a result of said reduction in said waterconcentration;

(j) forming thereby a substantially continuous dye impermeable polymericlayer disposed intermediate said dyeable polymeric layer and saidblue-sensitive silver halide emulsion layer; and

(k) maintaining said laminate intact subsequent to said processing.

39. A process as defined in claim 38 wherein said first pH is above 9and said second pH is below 9.

40. A process as defined in claim 38 including the step of separatingsaid container from said laminate subsequent to substantial imageformation.

41. A process as defined in claim 38 wherein said opacifying agent isradiation reflective.

42. A process as defined in claim 41 wherein said opacifying agent istitanium dioxide.

43. A process as defined in claim 38 wherein said aqueous alkalineprocessing solution insoluble polymeric dispersion comprisescarboxylated styrene/butadiene copolymer.

44. A process as defined in claim 43 wherein said aqueous alkalineprocessing solution insoluble polymeric dispersion is present in aconcentration of about 5 to 40 g. of polymer/ 100 cc. of processingsolution water.

References Cited UNITED STATES PATENTS 2,584,029 1/1952 Land 96-29NORMAN G. TORCHIN, Primary Examiner A. T. SURO PICO, Assistant ExaminerUS. Cl. X.R. 96-2, 76

